U.S. patent application number 10/385519 was filed with the patent office on 2004-09-16 for power interrupt system for a refrigerated appliance.
Invention is credited to Miller, Alvin V., Ryner, Joseph H., VanMeter, Kyle B., Wetekamp, Robert L..
Application Number | 20040177625 10/385519 |
Document ID | / |
Family ID | 33518354 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040177625 |
Kind Code |
A1 |
Miller, Alvin V. ; et
al. |
September 16, 2004 |
POWER INTERRUPT SYSTEM FOR A REFRIGERATED APPLIANCE
Abstract
A refrigerated appliance includes a power interrupt system for
detecting an out-of-range temperature condition in a fresh food or
freezer compartment after a power interruption. The power interrupt
system includes a central processor including a memory storage
module and a plurality of temperature sensors. In operation, the
power interrupt system compares sensed temperature values with
stored temperature variables. If, after a power interruption, a
compartment temperature exceeds a stored temperature variable by a
defined amount, an over-temperature flag is triggered. Preferably,
a display unit flashes an indication of the highest temperature
reached by each compartment intermittently with the current
compartment temperatures and an indication that a power
interruption has occured. In this manner, a consumer can make an
informed determination whether food stored within the appliance has
been exposed to temperatures high enough to cause spoilage.
Inventors: |
Miller, Alvin V.; (Swisher,
IA) ; Ryner, Joseph H.; (New Windsor, IL) ;
VanMeter, Kyle B.; (Galesburg, IL) ; Wetekamp, Robert
L.; (Cedar Rapids, IA) |
Correspondence
Address: |
DIEDERIKS & WHITELAW, PLC
12471 Dillingham Square, #301
Woodbridge
VA
22192
US
|
Family ID: |
33518354 |
Appl. No.: |
10/385519 |
Filed: |
March 12, 2003 |
Current U.S.
Class: |
62/129 ; 236/94;
374/E3.002 |
Current CPC
Class: |
G01K 3/005 20130101;
F25D 2400/361 20130101; F25D 29/008 20130101; F25D 2700/12
20130101; F25D 2700/122 20130101 |
Class at
Publication: |
062/129 ;
236/094 |
International
Class: |
G05D 023/00; G01K
013/00 |
Claims
I/We claim:
1. A method of detecting an over-temperature condition in fresh
food and freezer compartments of a refrigerator after a power
interruption comprising: initializing, in a first variable set,
values being defined by an interrupt temperature for each of the
fresh food and freezer compartments; setting a second variable set
as the value of the current sensed temperature for each of the
fresh food and freezer compartments; detecting the power
interruption and subsequent re-initialization of power to the
refrigerator; sensing a post power interrupt temperature for each
of the fresh food and freezer compartments; establishing the
over-temperature condition if either the fresh food or freezer
compartment post interrupt temperature exceeds the values
established in either the first or second variable sets by
respective predetermined amounts; and providing an indication when
the over-temperature condition exists.
2. The method according to claim 1, wherein the interrupt
temperature is defined by a lowest possible set point temperature
for the fresh food and freezer compartments respectively.
3. The method according to claim 1, further comprising:
establishing the over-temperature condition if either the fresh
food or freezer compartment post power interrupt temperature
exceeds the values of the first variable set by at least 3.degree.
F.
4. The method according to claim 1, further comprising:
establishing the over-temperature condition if the post power
interrupt temperature for either the fresh food or freezer
compartment exceeds the value of the second variable set by at
least 2.degree. F.
5. The method according to claim 1, wherein providing the
indication of the over-temperature condition comprises
intermittently flashing a visual indication of the over-temperature
condition on a display console.
6. The method according to claim 1, wherein providing the
indication of the over-temperature condition comprises sounding an
audible alarm.
7. The method according to claim 1, wherein providing the
indication of the over-temperature condition constitutes providing
a visual indication of the highest temperature reached within each
of the respective fresh food and freezer compartments, resulting
from the power interruption, on a display console.
8. The method according to claim 7, further comprising: displaying
an indication of the current temperature within each of the
respective fresh food and freezer compartments on the display
console.
9. The method according to claim 1, further comprising: replacing
the values in the first variable set with the respective post power
interrupt temperatures.
10. The method according to claim 1, further comprising:
continuously monitoring each of the fresh food and freezer
compartments for the occurrence of the over-temperature
condition.
11. The method according to claim 1, further comprising: resetting
the variables stored in the first and second variable sets.
12. A method of detecting an over-temperature condition in a
refrigerator having fresh food and freezer compartments after a
power interruption comprising: initializing, in a first variable
set, a value being defined by an interrupt temperature for at least
one of the fresh food and freezer compartments; setting a second
variable set as a value of a current sensed temperature for the at
least one of the fresh food and freezer compartments; detecting the
power interruption and subsequent re-initialization of power to the
refrigerator; sensing a post power interrupt temperature for the at
least one of the fresh food and freezer compartments; establishing
the over-temperature condition if the post interrupt temperature
exceeds the values established in either the first or second
variable sets by respective predetermined amounts; replacing the
value in the first variable set with the post power interrupt
temperature; and providing an indication of the over-temperature
condition.
13. The method according to claim 12, wherein the interrupt
temperature is defined by a lowest possible set point temperature
for the at least one of the fresh food and freezer
compartments.
14. The method according to claim 12, further comprising:
establishing the over-temperature condition if the post power
interrupt temperature exceeds the value stored in the first
variable set by at least 3.degree. F.
15. The method according to claim 12, further comprising:
establishing the over-temperature condition if the post power
interrupt temperature exceeds the value stored in the second
variable set by at least 2.degree. F.
16. The method according to claim 12, wherein providing the
indication of the over-temperature condition comprises
intermittently flashing a visual indication of the over-temperature
condition on a display console.
17. The method according to claim 12, wherein providing the
indication of the over-temperature condition comprises sounding an
audible alarm.
18. The method according to claim 12, wherein providing the
indication of the over-temperature condition constitutes visually
displaying a highest temperature reached within the at least one of
the fresh food and freezer compartments resulting from the power
interrupt.
19. The method according to claim 12, further comprising:
continuously monitoring the at least one of the fresh food and
freezer compartments for the occurrence of the over-temperature
condition.
20. The method according to claim 12, further comprising: resetting
the variables stored in the first and second variable sets.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention pertains to the art of refrigerated
appliances and, more particularly, to a refrigerated appliance
having a system for detecting an over-temperature condition in a
fresh food or freezer compartment resulting from an interruption of
power to the appliance.
[0003] 2. Discussion of the Prior Art
[0004] In general, refrigerated appliances include a freezer
compartment for maintaining foodstuffs at or below freezing, and a
fresh food compartment for maintaining foodstuffs in a temperature
zone below ambient temperature but above freezing temperatures. A
typical refrigerator includes an electrically powered refrigeration
system having at least a compressor, a condenser, a condenser fan,
an evaporator coil, evaporator fan and a plurality of temperature
sensors.
[0005] In operation, a consumer selects a desired temperature for
each of the fresh food and freezer compartments or, in the
alternative, a preset temperature value is provided by the
manufacturer. Once power is introduced to the appliance, the
refrigeration system operates to establish and maintain the
selected temperature within each of the fresh food and freezer
compartments. During periods of normal use, each of the
compartments is accessed several times during a typical day. Each
time a compartment door is opened, the temperature inside the
compartment rises due to an influx of warmer, ambient air. Sensors
arranged within the compartments function to detect any rise in
temperature, and in response, the refrigeration system is actuated
to return the affected compartment to the selected temperature.
Certainly, if the compartment is sealed, the refrigeration system
will operate for a short time period in order to re-establish the
selected temperature level. However, if the compartment remains
open, i.e. the consumer fails to properly close a compartment door,
the refrigeration system will operate continuously in order to try
to maintain the proper temperature level.
[0006] Obviously, with the door open, no matter how efficient the
refrigeration system, the temperature of the compartment will not
reach the desired level. The warmer, ambient temperature will enter
and raise the temperature of the unsealed compartment. Left
unchecked, the temperature could rise to a level that would
detrimentally affect food stored within the appliance. In addition
to problems associated with open appliance doors, compartment
temperatures will rise during periods of power interruption.
[0007] When power is interrupted to the appliance, the
refrigeration system is unable to function. Despite the existence
of seals about the appliance which prevent the influx of air to the
compartment, over time, ambient air will leak into the appliance.
The temperature of the compartment will rise, and if power is
interrupted for a prolonged period, food within the appliance will
spoil. When power is returned, the refrigeration system will
operate normally, pulling down the compartment temperature to the
selected level. Left unaware, the consumer may inadvertently
consume spoiled food items.
[0008] Therefore, based on the above, there exists a need in the
art of refrigerators for a power interrupt system that provides an
indication to a consumer of an over-temperature condition developed
during periods of power interruption. Specifically, to a power
interrupt system which will display to the consumer the highest
temperature reached during the period of the power interruption so
that an informed decision can be made as to the likelihood that the
food stored within the appliance has spoiled.
SUMMARY OF THE INVENTION
[0009] The present invention is directed to an power interrupt
system for a refrigerated appliance. More particularly, the power
interrupt system is provided to detect an out-of-range temperature
condition for fresh food and freezer compartments of the
refrigerated appliance after the occurrence of a power
interruption. In accordance with one form of the present invention,
the power interrupt system includes a control unit having a
temperature selector element, a central processor including a
memory storage module, and a plurality of temperature sensors
arranged about the appliance. The temperature sensors, in
combination with the control unit, function to monitor fresh food
and freezer compartment temperatures and activate a refrigeration
system upon a sensed cooling demand. In operation, the power
interrupt system compares sensed temperature values with stored
temperature variables. If, after a power interruption, the sensed
temperatures exceed the stored temperature variables by a
predetermined amount, a power interrupt or over-temperature flag is
triggered.
[0010] In accordance with another preferred form of the invention,
a first variable set, defined by an interrupt temperature for each
of the fresh food and freezer compartments, is stored in the memory
module. Preferably, the interrupt temperature represents the lowest
possible temperature setting for the respective refrigerator
compartment. A second variable set, defined by a current set point
temperature for each compartment, is also stored in the memory
module. Upon activation, after sensing a power interruption and
subsequent re-initialization of power to the appliance, the control
unit begins monitoring the post power interrupt temperatures for
the compartments. Each time the control unit scans post power
interrupt temperatures for the compartments, the values obtained
are compared to the values stored in the first and second variable
sets. If the current post power interrupt temperature exceed the
corresponding value stored in the first or second variable sets, an
out of temperature range flag is triggered and a visual indication
to this effect is displayed to the consumer.
[0011] In the most preferred form of the invention, the
refrigerated appliance includes an exteriorly mounted control panel
having an alpha-numeric display. Once the out-of-range temperature
flag is triggered, an alarm indicating the over temperature
condition is activated. In the most preferred form, the display
flashes the out-of-range temperature value for a particular
compartment intermittently with the current compartment temperature
value. More specifically, the display is continuously updated such
that the highest temperature value realized by the compartment is
displayed to the consumer. In addition to the out-of-range
temperatures, the display will provide the consumer with an
indication that a power interruption has occurred. This can take
the form of a flashing display, an audible signal, or a combination
thereof. In this manner, the consumer can decide if the compartment
temperature was elevated to a point that would necessarily result
in spoilage to the food stored within the compartment. Preferably,
the display will continue to flash the alarm until a reset button
is manipulated, thus ensuring that the consumer was made aware of
the alarm condition.
[0012] Additional objects, features and advantages of the present
invention will become more readily apparent from the following
detailed description of a preferred embodiment when taken in
conjunction with the drawings wherein like reference numerals refer
to corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a front view of a refrigerated appliance employing
the power interrupt system of the present invention;
[0014] FIG. 2 is a partially exploded view showing various
components of the power interrupt system of the present
invention;
[0015] FIG. 3 is a block diagram depicting the interrelationship
between components of the power interrupt system of FIG. 2; and
[0016] FIG. 4 is a flow diagram setting forth a preferred control
algorithm for the method of operating the power interrupt system of
the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] With initial reference to FIG. 1, a refrigerator having a
power interrupt system constructed in accordance with the present
invention is generally indicated at 2. Refrigerator 2 is shown to
include a freezer door 6 having an associated handle 7 and a fresh
food door 10 having an associated handle 11. In the embodiment
shown, refrigerator 2 is of the recessed type such that,
essentially, only freezer and fresh food doors 6 and 10 project
forward of a wall 15. The remainder of refrigerator 2 is recessed
within wall 15 in a manner similar to a plurality of surrounding
cabinets generally indicated at 18-23. Refrigerator 2 also includes
a plurality of peripheral trim pieces 28-30 to blend refrigerator 2
with cabinets 18-23. One preferred embodiment employs trim pieces
28-30 as set forth in commonly assigned U.S. patent application
entitled "Fastening System for Appliance Cabinet Assembly" filed on
even date herewith and which is incorporated herein by
reference.
[0018] In another preferred embodiment, refrigerator 2 is
preferably designed with main components of a refrigeration system
positioned behind an access panel 32 arranged directly above trim
piece 29. In one preferred form of the invention, as will be
detailed more fully below, a control and display unit 34 is mounted
to an upper portion of freezer door 6. More specifically, control
and display unit 34 constitutes an electronic control panel 35
having arranged thereon a plurality of control elements 36 to enter
desired operating temperatures and a digital display 37 to show
temperature set points and/or actual compartment temperatures.
Preferably, control and display unit 34 includes consumer operated
switches to change the displays from .degree. F. to .degree. C. and
vise versa, various alarm indications, such as power interruption
and door ajar indicators, service condition signals and, in models
incorporating water filters, a filter change reminder.
[0019] As shown in FIG. 2, refrigerator 2 includes a cabinet shell
38 defining a freezer compartment 40 and a fresh food compartment
43. For details of the overall construction of cabinet shell 38,
reference is again made to the above-identified U.S. patent
application entitled "Fastening System for Appliance Cabinet
Assembly." Shown arranged on a rear wall 44 of fresh food
compartment 43 are a plurality of elongated metal shelf rails 46.
Each shelf rail 46 is provided with a plurality of shelf support
points, preferably in the form of slots 47, adapted to accommodate
a plurality of vertically adjustable, cantilevered shelves (not
shown). Since the manner in which such shelves can be constructed
and supported may vary and is not considered part of the present
invention, the shelves have not been depicted for the sake of
clarity of the drawings and will not be discussed further here.
However, for purposes which will be set forth further below, it
should be noted that each of rails 46 preferably extends from an
upper portion, through a central portion, and down into a lower
portion (each not separately labeled) of fresh food compartment
43.
[0020] In the embodiment shown, mounted behind access panel 32 are
various components of the refrigeration system employed for
refrigerator 2. More specifically, the refrigeration system
includes at least a variable speed compressor 49, an evaporator 52
and a condenser 61. Preferably, each of the components is operated
in an optimum manner based upon sensed cooling demand within
refrigerator 2.
[0021] In addition to the aforementioned components, mounted to an
upper portion of fresh food compartment 43 is an air manifold 90
for use in directing a cooling airflow through fresh food
compartment 43 of refrigerator 2. More specifically, interconnected
to air manifold 90 are a first recirculation duct 94 having an
inlet 95 exposed in a lower portion of fresh food compartment 43, a
second recirculation duct 96 having an inlet 97 exposed at an upper
portion of fresh food compartment 43, and an intake duct 100
establishing an air path for a flow of fresh cooling air from
freezer compartment 40 into manifold 90. Arranged in fluid
communication with air manifold 90 is a fresh food stirring fan
110. Stirring fan 110 is adapted to receive a combined flow of air
from recirculation ducts 94 and 96, as well as intake duct 100, and
to disperse the combined flow of air into the fresh food
compartment 43. With this arrangement, stirring fan 110 draws in a
flow of air, which is generally indicated by arrows A, through
inlets 95 and 97 of ducts 94 and 96, and intake duct 100, while
subsequently exhausting the combined flow of cooling air,
represented by arrow B, through an outlet 125. Most preferably,
outlet 125 directs the air flow in various directions in order to
generate a desired flow pattern based on the particular
configuration of fresh food compartment 43 and any additional
structure provided therein. The exact positioning of inlets 95 and
97 also depend on the particular structure provided. In one
preferred arrangement, inlet 95 of duct 94 is located at a point
behind at least one food storage bin (not shown) arranged in a
bottom portion of fresh food compartment 43. The air flow past the
storage bin is provided to aid in maintaining freshness levels of
food contained therein. For this purpose, an additional passage
leading from freezer compartment 40 into fresh food compartment 43
can be provided as generally indicated at 128. While not part of
the present invention, the details of the storage bin are described
in commonly assigned U.S. Pat. No. 6,170,276 which is hereby
incorporated by reference.
[0022] In order to regulate the amount of cooling air drawn in from
freezer compartment 40, a multi-position damper 130 is provided
either at an entrance to or within intake duct 100. When the
cooling demand within fresh food compartment 43 rises, damper 130
opens to allow cooling air to flow from freezer compartment 40 to
fresh food compartment 43 and, more specifically, into intake duct
100 to manifold 90 and stirring fan 110. A flow of air to be
further cooled at evaporator 52 is lead into an intake 135 of a
return duct 137. In the embodiment shown, return duct 137 is
preferably located in the upper portion of fresh food compartment
43. For details of the overall operation and arrangement of the
temperature control system of refrigerator 2, reference is made to
commonly assigned U.S. patent application entitled "Temperature
Control System for a Refrigerated Compartment" filed on even date
herewith and which is hereby incorporated by reference.
[0023] It should be understood that the above description is
provided for the sake of completeness and that the present
invention is particularly directed to a power interrupt system for
refrigerator 2. More particularly, the power interrupt system
detects an over-temperature condition and provides an indication of
the highest temperature reached within either freezer compartment
40 or fresh food compartment 43 after a period of power
interruption to refrigerator 2.
[0024] Reference will now be made to FIG. 3 depicting a preferred
embodiment of the present invention. As shown, a power interrupt
system 160 includes a central processor or CPU 170 having a memory
storage module 173. CPU 170 is adapted to receive input signals
from control and display unit 34, in addition to a plurality of
temperature sensors, two of which are constituted by a freezer
temperature sensor 180 and a fresh food temperature sensor 185
(also shown in FIG. 2). Power interrupt system 160 is selectively
activated through one of the plurality of control elements 36 on
control and display unit 34. Upon activation, power interrupt
system 160 monitors the temperature of freezer compartment 40 and
fresh food compartment 43 after detecting a power interruption.
Once power is restored to refrigerator 2 following a power failure,
as will be detailed more fully below, power interrupt system 160
determines if the temperature of either freezer compartment 40 or
fresh food compartment 43 exceeds a predetermined value. If so,
power interrupt system 160 outputs to digital display 37 an
indication of the highest temperature reached in each compartment
until a reset button 189 is activated.
[0025] Having described various of the components of power
interrupt system 160, a preferred method of operation will be set
forth with particular reference to FIG. 4 depicting a preferred
control algorithm. Upon application of electrical power to
refrigerator 2, control and display unit 34 and power interrupt
system 160 are initialized in step 195. During the initial start-up
sequence, a first variable set, defined by a value representing the
respective set point temperatures for each of the freezer and fresh
food compartments 40 and 43, is established. Simultaneously, a
second variable set, defined by a value representing an interrupt
temperature, is also established. In accordance with this preferred
embodiment, the interrupt temperature values constitute the lowest
possible temperature setting for each compartment. In any event,
the respective variable sets are stored in memory storage module
173.
[0026] After an the initial power-up, be it through an initial
application of power to the system or after a power interruption,
temperature sensors 180 and 185 are polled in step 197 to determine
current temperature values for both the freezer and fresh food
compartments 40 and 43. After determining the current temperature
values for the respective compartments, in step 199, a
determination is made whether power interrupt system 160 is
enabled. If, in step 199, power interrupt system 160 is determined
to be enabled, then, in step 201, the current temperature value for
each compartment is compared to the values stored in the first
variable set.
[0027] If, after performing step 201, either the freezer or fresh
food compartment temperatures are found to exceed the corresponding
values stored in the first variable set by more than a first
predetermined amount, preferably at least 3.degree. F., a power
interrupt or over-temperature trip flag is established in step 205.
Once the over-temperature flag is enabled, the value stored in the
second variable set, corresponding to the temperature values found
to satisfy the requirement of step 201, is replaced with the new
values in step 206. After the completion of step 206, the process
moves to step 207 in which digital display 37 is caused to
alternately flash a power interrupt signal, the current temperature
of both the freezer and fresh food compartments 40 and 43 and the
new value or values stored in the second variable set. In addition,
an audible warning may accompany the visible warning provided by
digital display 37. With this arrangement, the consumer is provided
with an indication that a power interrupt has occurred and,
additionally, the highest temperature reached by either compartment
during the power interrupt, as well as current compartment
temperatures.
[0028] Conversely, if in step 201 neither of the current
temperature values sensed in step 197 exceeds the values stored in
the first variable set by the predetermined value, the control
algorithm moves to step 210 in which the current temperatures are
compared to the values stored in the second variable set. In a
manner similar to that described above, if the current temperature
values exceed the values stored in the second variable set by a
second predetermined amount, preferably at least 2.degree. F.,
power interrupt system 160 performs steps 205-207.
[0029] In either case, digital display will continue to perform
step 207 until, in step 211, it is determined that reset button
189, is actuated. After reset control 189 is actuated, signaling
that the consumer is made aware of the power interrupt and any
resulting rise in temperature, the control algorithm moves to steps
213-215 before terminating at step 220. In step 213 digital display
37 ceases to flash the warning established in step 207. Next, the
power interrupt trip flag is disabled in step 214 and, finally, in
step 215, the values stored in the second variable set are reset to
the minimum set point temperatures establish at the onset of the
process.
[0030] Although described with reference to a preferred embodiment
of the invention, it should be readily understood that various
changes and/or modifications can be made to the invention without
departing from the spirit thereof. For instance, the particular
location of the control and display unit is not important so long
as it provides the consumer with a readily visible indication of
the status of the appliance. Additionally, the particular
temperature values that trigger the power interrupt system can be
varied without departing from the scope of the present invention.
Finally, while the refrigeration system is described as being
operable with variable speeds, it should be understood that the
power interrupt system of the present invention is applied to
standard refrigeration systems as well. In general, the invention
is only intended to be limited by the scope of the following
claims.
* * * * *